The invention pertains to the art of self-loading scrapers having a dirt collecting bowl with an elevator mechanism inclined downwardly at the front of the bowl to assist in moving the dirt off of the scraper blade and into the bowl.
1. Field of the Invention
The larger sized industrial scrapers will normally be towed by a special, heavy duty, two-wheeled prime mover. The elevator is driven by an elevator drive group, typically an hydraulic motor and reduction gearing powered by an hydraulic pump driven off of the engine of the prime mover.
For smaller sized scrapers of generally under 10 cubic yards capacity, often referred to as utility or agricultural scrapers, a lower horsepowered tractor may be used and most commonly a four-wheel farm tractor having a hitch and a power takeoff. An elevator drive line is attached to the power takeoff of the tractor for driving the elevator through a gear box mounted at the top and on one end of the elevator drive shaft. A two-wheeled utility scraper of the type referred to is disclosed in U.S. Pat. No. 3,090,139 entitled 37 Two Wheeled Scraper" issued May 21, 1963 which by mesne assignment is assigned to the assignee of the present invention.
The present invention will most advantageously be employed and find its greatest application in the smaller sized or utility scraper field, although it should be appreciated that many of the features of the invention are applicable equally to the industrial scrapers.
2. Description of Prior Art
With the two-wheeled utility scraper of the type disclosed in the aforementioned U.S. Pat. No. 3,090,039, the elevator is driven by a gear box mounted on one end of the elevator drive shaft at the top of the elevator. The drive line from the tractor power takeoff to the gear box is required to take a somewhat tortuous path considering the lower position of the power takeoff and the higher, offset position of the gear box.
Also, since it is necessary that the tractor be turned with respect to the center line of the scraper, the drive line must employ several telescoping sections, special pivot bearings and a number of U-joints in order to maintain effective drive to the elevator.
With the small two-wheeled utility scraper, such as shown in the aforementioned patent, there is no suspension. The wheels are directly mounted on the scraper body such that if the scraper encounters a rock or any change in elevation, a substantial change in the blade height is unavoidable, making it difficult to produce a uniform depth of cut.
Moreover, because only two wheels are supporting the load the tire width must be greater to provide lateral support and distribute the ground pressure. Consequently, wide side blade extensions or moldboards are required to cut out the tread width.
Heretofore the scraper bowl has been an all welded construction believed to be required for greater strength and rigidity. Welding fabrication of the bowl takes place at the factory. Assembly of certain other components, such as the elevator, may be performed by the customer. However, the greatest bulk is the bowl and for all practical purposes the largest portion of the freight charge is for the bowl. This is a factor which is believed to have detracted from wider usage particularly of the utility scraper.
To our knowledge there has been no scraper before now especially designed for shipment in knocked down form, that is, where the various components, including the scraper bowl, are shipped disassembled in a compact, banded or crated form to obtain maximum utilization of shipping space.